Geoscience Reference
In-Depth Information
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Position of the source
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Position of the source
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(m)
1st layer thickness (m)
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Seismic magnitude
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Joint inversion seismograms and electrograms
Inversion seismograms alone
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Figure 5.10
Posterior probability density function of the seven model parameters computed from the seismic and electric data with
15% noise level (2000 realizations in total, convergence reached after iteration 1356). The solid vertical bars indicate the true value
of the model parameters. The joint inversion of the seismograms and electrograms does a better job than the inversion of the
seismograms alone, in getting closer to the true values of the model parameters.
data is less than the information content of the electri-
cal data.
True model
5.2.5 Hybrid joint inversion
Next, we provide a more efficient algorithm that could be
applied to real data. First, we start with a deterministic
algorithm using only the electrical data to invert for the
position of the seismic source as well as the position of
any heterogeneity located along the wave fronts using
the approach developed recently by Araji et al. (2012).
Then, once the position and time of occurrence of the
seismic source and the position of heterogeneities are
estimated, we switch to the AMA to determine the pos-
terior probability functions of the independent compo-
nents of the moment tensor to find the moment tensor
with the highest likelihood.
Here, we show that the position of the source and
the position of the heterogeneities within the wave field
between source and receivers can be imaged using only
the electrical potential signals. At the scale of this exer-
cise, the seismic source geometry and associated seismic
wavelength, along with the seismic related electrical
All seismic-based
source models
All electric-based
source models
Figure 5.11
Information content for noise-free data. True
information content for the joint inversion problem. The
electrical field contains more information than the seismic field
under the condition that the same level of noise is applied to the
seismograms and electrograms.
with the inversion of the seismic data alone. In terms of
information content, we can draw the sketch shown in
Figure 5.11. For the same level of noise in the seismic
and electrical data, the information content of the seismic
